Causes and Symptoms (Magill’s Medical Guide, Sixth Edition)
Cyanosis, a dark blue discoloration of the skin and nail beds, is a sign of a disorder, not a disease in itself, and it may have several causes. It is also not a symptom sensed by a patient but a physical finding. To appear, cyanosis requires a concentration in arterial blood of 4 to 5 grams per deciliter of reduced hemoglobin. Anemic patients may not show cyanosis even though their hemoglobin saturations are low. Its presence indicates one or more of the following: inadequate oxygenation of arterial blood (a decrease of oxygen saturation to 85 percent or less), the presence of a normal constituent (methemoglobin) in increased concentration, or the presence of an abnormal constituent (sulfhemoglobin).
Inadequate oxygenation of normally circulating blood. The obstruction of large airways (the tracheobronchial system) can occur from external compression or the aspiration of solid or semisolid materials (foodstuffs, particularly ground meat). Laryngospasm may be a factor. The aspiration of aqueous fluids, as in drowning in freshwater, can fill the alveoli and decrease or prevent the contact of inspired air with the blood in the pulmonary capillaries. Freshwater can pass rapidly into the blood and eventually free the alveoli for gas exchanges. Drowning in seawater is usually accompanied by marked laryngospasm. If the hypertonic seawater reaches the alveoli, then water will cross from the blood into the alveoli and...
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Treatment and Therapy (Magill’s Medical Guide, Sixth Edition)
Treatment is directed not to the cyanosis itself but to the underlying problem. Oxygen administration is crucial in many but not all cases.
For airway obstruction, the Heimlich maneuver may be lifesaving, as may an emergency tracheostomy. Drowning requires artificial respiration, positioning of the body so that drainage of fluid from the lungs is facilitated, and administration of oxygen, if available. Full cardiopulmonary resuscitation (CPR) may be indicated. Pulmonary edema from cardiac failure or respiratory distress syndrome calls into use a variety of approaches, but oxygen is almost always provided. Artificial respiration and oxygen are usually required in heroin, morphine, and ethchlorvynol pulmonary edema. COPD and emphysema are chronic, progressive disorders in which oxygen, bronchodilators, antibiotics, steroids, and surgical interventions (lung volume reduction) may be used. In methemoglobinemia, the congenital forms may not require any treatment. If the cyanosis is the result of exposure to nitrites and other potential oxidants, then methylene blue is usually effective.
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Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
Cyanosis has been recognized for centuries as a sign or indicator of an underlying problem. The focus of investigations has been on identifying these problems. The properties of the hemoglobins have been investigated by physiologists and hematologists, leading to an understanding of their structures and functions. Surgical correction of the vascular abnormalities of so-called blue babies by Alfred Blalock and Helen Taussig led to the opening of the field of cardiovascular surgery. Molecular biology has provided knowledge of the enzymatic and genetic factors involved in the development of methemoglobinemia.
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For Further Information: (Magill’s Medical Guide, Sixth Edition)
Dickerson, Richard E., and Irving Geis. Hemoglobin: Structure, Function, Evolution, and Pathology. Menlo Park, Calif.: Benjamin/Cummings, 1983.
Icon Health. Cyanosis: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, Calif.: Author, 2004.
Nagel, Ronald L., ed. Hemoglobin Disorders: Molecular Methods and Protocols. Totowa, N.J.: Humana Press, 2003.
Weibel, Ewald R. The Pathway for Oxygen: Structure and Function in the Mammalian Respiratory System. Cambridge, Mass.: Harvard University Press, 1984.
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Cyanosis (Encyclopedia of Medicine)
Cyanosis is a physical sign causing bluish discoloration of the skin and mucous membranes. Cyanosis is caused by a lack of oxygen in the blood. Cyanosis is associated with cold temperatures, heart failure, lung diseases, and smothering. It is seen in infants at birth as a result of heart defects, respiratory distress syndrome, or lung and breathing problems.
Blood contains a red pigment (hemoglobin) in its red blood cells. Hemoglobin picks up oxygen from the lungs, then circulates it through arteries and releases it to cells through tiny capillaries. After giving up its oxygen, blood circulates back to the lungs through capillaries and veins. Hemoglobin, as well as blood, is bright red when it contains oxygen, but appears dark or "bluish" after it gives up oxygen.
The blue discoloration of cyanosis is seen most readily in the beds of the fingernails and toenails, and on the lips and...
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Cyanosis (Encyclopedia of Nursing & Allied Health)
Cyanosis is a physical state characterized by bluish discoloration of the skin and mucus membranes.
Cyanosis is a physical sign, rather than a diagnosis. The abnormal coloring of a cyanotic patient is due to a low oxygen content of the circulating red blood cells. Typically the abnormal bluish coloring is most noticeable in the nailbeds, lips, ears, and cheeks.
Causes and symptoms
One of the many important functions of blood is to pick up oxygen from the air sacs of the lungs and deliver it to sites around the body in need of oxygen. To carry oxygen, red blood cells (RBCs) contain a pigment called hemoglobin. When hemoglobin is carrying its full capacity of oxygen, it will cause the RBC to appear bright red. After the oxygen has been delivered, the RBC has a darker, bluish cast. If the darker-colored RBCs predominate, this gives the skin and mucus membranes the characteristic blue appearance of cyanosis.
There are two basic types of cyanosis: central and peripheral. Central cyanosis means that the arterial blood simply does not contain normal levels of oxygen (hypoxemia). This can happen because of lung disease, heart defects, and certain problems with the hemoglobin itself. Peripheral cyanosis means that venous blood (or blood that has unloaded its oxygen) is contributing to skin color more than arterial (or oxygen-rich) blood. A patient may have normal oxygen levels in arterial blood, but still have the bluish color of cyanosis expressed in some part(s) of his body. With peripheral cyanosis the underlying condition may be exposure to the cold, or decreased output from the heart, or local disruptions in the flow of arterial or venous blood.
Patients may or may not have symptoms with cyanosis, depending on its cause. With central cyanosis patients are often short of breath, dizzy, or even unconscious. With a peripheral cause of cyanosis, patients may have complaints localized to the affected parts of the body.
Cyanosis is a subjective observation, so there is no test to confirm it. A patient's skin pigmentation and the presence or absence of anemia can make cyanosis more or less obvious. But there are objective tests to verify the presence or absence of hypoxemia (or low oxygen content of the blood). A non-invasive pulse oximeter can be used by a nurse or respiratory therapist to give a fairly accurate approximation of arterial oxygenation, and arterial blood gases can be drawn by a physician or respiratory therapist if detailed information is needed. If the arterial oxygen level is low, the cyanosis is central; if the oxygen level is normal, the cyanosis is peripheral in nature. If the affected body parts regain normal color with massage and warming, the cause was peripheral. Occasionally cyanosis has both central and peripheral elements.
Treatment of cyanosis is based on identifying and treating its cause, and restoring normal flow of oxygenated blood.
Prognosis is dependent on the disease process under- lying the cyanosis. If the underlying condition (such as heart or lung disease) can be properly treated, the skin will return to its normal coloring.
Health care team roles
Health care team members should be alert to cyanosis as a warning sign, particularly as a new development in a given patient. Prompt recognition and treatment could be very important to clinical outcome.
Hemoglobin colored substance (pigment) in the red blood cell that carries oxygen to tissues and gives blood its red color.
Pulse oximeter painless device which uses a beam of light directed through the patient's finger, toe or earlobe to assess oxygen saturation of the blood.
Braunwald, Eugene, et al. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 2001.
Carolson, Karen J., Stephanie A. Eisenstat, and Terra Ziporyn. The Harvard Guide to Women's Health. Cambridge, MA: Harvard University Press, 1996.
Erika J. Norris